First of all I know how you feel.... Of all the written tests I had to take (8 or 9), the first instrument seemed to be the hardest. But this was also where I learned the most.

ALL FAA test question banks are public. Thats why ASA and Gleimm are able to publish the study guides. So with that said, it is worth it to memorize alot of the questions. BUT you definitely need to understand them too. If it takes you a little longer to prepare for the test so what? It would be much more beneficial for you in the long run to take a little more time to understand the information than to rush through it and get a 70%.

Just my 2 cents though...